Tissue compression device for cardiac valve repair

ABSTRACT

The present disclosure describes interventional devices, systems, and methods for closing a regurgitant gap in a cardiac valve. Interventional devices are configured to be deployed between two previously placed implants or between a previously placed implant and a valve commissure. The interventional devices compress captured leaflet tissue and/or apply a tensioning force along the line of coaptation to assist in closing the gap and reducing regurgitant flow through the gap.

BACKGROUND

The mitral valve controls blood flow from the left atrium to the leftventricle of the heart, preventing blood from flowing backwards from theleft ventricle into the left atrium so that it is instead forced throughthe aorta for distribution throughout the body. A properly functioningmitral valve opens and closes to enable blood flow in one direction.However, in some circumstances the mitral valve is unable to closeproperly, allowing blood to regurgitate back into the atrium. Suchregurgitation can result in shortness of breath, fatigue, heartarrhythmias, and even heart failure.

Mitral valve regurgitation has several causes. Functional mitral valveregurgitation (FMR) is characterized by structurally normal mitral valveleaflets that are nevertheless unable to properly coapt with one anotherto close properly due to other structural deformations of surroundingheart structures. Other causes of mitral valve regurgitation are relatedto defects of the mitral valve leaflets, mitral valve annulus, or othermitral valve tissues. In some circumstances, mitral valve regurgitationis a result of infective endocarditis, blunt chest trauma, rheumaticfever, Marfan syndrome, carcinoid syndrome, or congenital defects to thestructure of the heart. Other cardiac valves, in particular thetricuspid valve, can similarly fail to properly close, resulting inundesirable regurgitation.

Heart valve regurgitation is often treated by repairing the faulty valvethrough an interventional procedure. In some circumstances, adjacentleaflets of the faulty valve are grasped and brought together using aninterventional clip. The interventional clip is intended to remaindeployed at the repaired valve to promote better coaptation of thegrasped leaflets and to thereby reduce regurgitant flow through thevalve. Although such a procedure may be beneficial, residualregurgitation can sometimes remain. A need therefore exists forsolutions which further improve cardiac valve repair and associatedpatient outcomes.

The subject matter claimed herein is not limited to embodiments thatsolve any disadvantages or that operate only in environments such asthose described above. Rather, this background is only provided toillustrate one exemplary technology area where some embodimentsdescribed herein may be practiced.

BRIEF SUMMARY

The present disclosure is directed to devices, systems, and methods fortreating regurgitant leaks in cardiac valve tissue, including leaksalong the cardiac valve line of coaptation. In some implementations,interventional device embodiments described herein may be deployed atgaps disposed between two previously deployed implants, or between apreviously deployed implant and a valve commissure.

In one embodiment, an interventional device for compressing cardiacvalve tissue at a targeted gap includes a distal member and a pair ofopposing arms flexibly joined to the distal member. Each arm extendsproximally from the distal member to a free end. The pair of opposingarms define an interior space between the arms for holding cardiac valvetissue. The arms have a default position and are flexibly moveable apartfrom one another away from the default position to increase the size ofthe interior space and to enable grasping of cardiac valve tissue withinthe interior space. The arms are configured to be biased toward thedefault position when moved apart from one another. In this manner, thearms provide a compressive force upon cardiac valve tissue held withinthe interior space.

In some embodiments, the interventional device is configured in size andshape for deployment at a targeted gap measuring about 2 mm to about 8mm, or about 2 mm to about 5 mm. The interventional device may thereforebe used in anatomical locations and/or under circumstances wheredeployment of a conventional clip (typically measuring 15 mm in lengthand 5 mm in width when closed) is improper. For example, aninterventional device as described herein may be deployed between twoconventional clips or between a conventional clip and a valvecommissure. Such gaps may not provide sufficient space for deployment ofanother conventional clip, or may not provide sufficient space for therequired articulation and maneuvering of a conventional clip.

In some embodiments, one or both of the free ends may flare outwardly.Some embodiments include an attachment point at the distal member forattaching to a delivery device. In some embodiments, one or both of thearms include a force-distributing pattern. In some embodiments, thedevice is formed from a shape-memory material such that the free ends,when deployed distally, sweep around proximally to grasp targetedcardiac valve tissue.

Some embodiments include an anchor configured to couple to the distalmember. The anchor extends through the interior space and has a widthgreater than the distal member or the arms. The anchor may be positionedon the atrial side of a targeted cardiac valve while the distal memberand arms are positioned on the ventricular side of the targeted valve.The anchor may include a textured surface for encouraging tissueingrowth. The anchor may have a width of about 5 mm to about 8 mm.

In one embodiment, the interventional device includes a first arm whichextends proximally from the distal member to form an inner member, and asecond arm which extends proximally from the distal member and loopsback distally to form a pair of outer members. The inner member islaterally offset from each of the outer members to avoid compressingtissue directly between any two of the arm members.

The interventional device may be deployed using a self-centeringdelivery catheter. The self-centering delivery catheter includes a pairof laterally extending fins extending from a distal section of thedelivery catheter. The fins are configured to enable alignment of thedelivery catheter with a line of coaptation at the targeted gap. In someembodiments, the self-centering delivery catheter is intra-procedurallyadjustable in width. In one embodiment, the self-centering deliverycatheter includes a pair of skives and a corresponding pair of wireslaterally extendable through the skives to form the fins. The wires mayextend through a lumen of the delivery catheter such that width of thefins is controllable via translation of the wires within the lumen.

One embodiment is directed to a method of reducing regurgitation througha cardiac valve by compressing leaflet tissue at a targeted gap of thecardiac valve. The method includes the steps of delivering aninterventional tissue compression device to the targeted gap, anddeploying the compression device at the targeted gap to compress theleaflet tissue and reduce regurgitant flow through the targeted gap. Thetargeted gap may be located at a mitral valve. The compression devicemay be delivered to the ventricular side of the mitral valve, thenretracted proximally to enable the arms to grasp the leaflet tissue atthe ventricular side of the mitral valve.

Additional features and advantages will be set forth in part in thedescription that follows, and in part will be obvious from thedescription, or may be learned by practice of the embodiments disclosedherein. The objects and advantages of the embodiments disclosed hereinwill be realized and attained by means of the elements and combinationsparticularly pointed out in the appended claims. It is to be understoodthat both the foregoing brief summary and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the embodiments disclosed herein or as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe various features and concepts of the presentdisclosure, a more particular description of certain subject matter willbe rendered by reference to specific embodiments which are illustratedin the appended drawings. Understanding that these figures depict justsome example embodiments and are not to be considered to be limiting inscope, various embodiments will be described and explained withadditional specificity and detail through the use of the accompanyingdrawings in which:

FIG. 1 illustrates an embodiment of a delivery system which may beutilized to deliver an interventional device to a targeted cardiacvalve;

FIG. 2 illustrates a human heart and shows an exemplary intravascularapproach by which a guide catheter of the delivery system of FIG. 1 maybe routed to the heart to deploy the interventional device;

FIG. 3A and 3B illustrate, in side view, deployment of a conventionalclip device at a mitral valve;

FIG. 4 illustrates a superior view of the mitral valve showing placementof conventional clip devices and showing gaps where residualregurgitation may occur;

FIGS. 5A through 5C illustrate an embodiment of a tissue tensioningdevice configured to be positioned within a targeted gap and to tensionleaflet tissue at the gap along the line of coaptation to aid in closingthe gap;

FIGS. 6A and 6B illustrate another embodiment of a tissue tensioningdevice;

FIGS. 7A and 7B illustrate deployment of a tissue compression deviceconfigured to grasp leaflet tissue at a targeted gap on the ventricularside of the mitral valve and to compress the tissue to aid in closingthe gap;

FIG. 8 illustrates alternative embodiments of tissue compressiondevices;

FIGS. 9A and 9B illustrate an embodiment of a tissue compression devicehaving an attached anchor member configured for placement on the atrialside of the mitral valve to prevent displacement of the tissuecompression device;

FIGS. 10A and 10B illustrate an embodiment of a tissue compressiondevice formed with a clip-like construction and having an inner memberoffset from two outer members to avoid compressing leaflet tissuedirectly between two arm members;

FIGS. 11A through 11C illustrate deployment of an embodiment of a tissuecompression device having shape memory, showing initial distaldeployment of the free ends of the device followed by the arms sweepingaround and extending proximally to engage leaflet tissue;

FIGS. 12A through 12D illustrate an embodiment of a combination tissuetensioning and tissue compression device configured to tension leaflettissue along the line of coaptation and to compress leaflet tissue toaid in closing a targeted gap;

FIGS. 13A through 13D illustrate various embodiments of aforce-distributing feature which may be utilized at portions of a tissuetensioning and/or compression device;

FIG. 14 illustrates an embodiment of a self-centering delivery catheterand/or sizer having a pair of fins for aligning the delivery catheterwith cardiac valve anatomy;

FIGS. 15A and 15B illustrate another embodiment of a self-centeringdelivery catheter having adjustable-width fins; and

FIGS. 16A through 16C illustrate various embodiments ofattachment/detachment mechanisms which may be used with theinterventional devices described herein.

DETAILED DESCRIPTION Introduction

The present disclosure is directed to devices, systems, and methods fortreating regurgitant leaks in cardiac valve tissue, including leaksalong the cardiac valve line of coaptation. In some implementations,interventional device embodiments described herein may be deployed atgaps disposed between two previously deployed implants, or between apreviously deployed implant and a valve commissure. The interventionaldevices may be deployed to apply a tensioning force along the line ofcoaptation and/or to compress captured leaflet tissue along a lineorthogonal to the line of coaptation to assist in closing a targeted gapand reducing regurgitant flow through the gap.

Throughout this disclosure, many examples are described in the contextof guiding a delivery system to a mitral valve. One of skill in the artwill understand, however, that the described components, features, andprinciples may also be utilized in other applications. For example, atleast some of the embodiments described herein may be utilized forguiding a delivery system to a pulmonary, aortic, or tricuspid valve.

Delivery System Overview

FIG. 1 illustrates a delivery system 100 which may be utilized todeliver an interventional device to a targeted cardiac valve. Theillustrated delivery system 100 includes a handle 102 and a guidecatheter 104 coupled to the handle 102. The handle 102 is connected tothe proximal end 108 of the guide catheter 104 and may be configured tobe operatively connected to one or more lumens of the guide catheter 104to provide steering control over the guide catheter 104.

An interventional device 106 may be passable through an inner lumen ofthe guide catheter 104 to the distal end 110. The interventional device106 generically represents any of the tensioning devices and/orcompression devices described herein, such as those illustrated in FIGS.5A through 13D. The interventional device 106 may be attached to asuitable delivery member 109 (e.g., delivery catheter, sheath, and/orpush rod such as those illustrated in FIGS. 14 through 16C) for deliverythrough the guide catheter 104. One or more controls 112 may be includedat the handle 102. The one or more controls 112 may be operativelycoupled to the guide catheter 104 to provide steering control (e.g., bytensioning one or more control wires).

FIG. 2 illustrates a schematic representation of a patient's heart and adelivery procedure that may be conducted using the illustrated deliverysystem 100. The guide catheter 104 may be inserted into the patient'svasculature and directed to the inferior vena cava 12. The guidecatheter 104 is passed through the inferior vena cava 12 toward theheart. Upon entering the heart from the inferior vena cava 12, the guidecatheter 104 enters the right atrium 14. For procedures associated withrepair of the mitral valve 20, the guide catheter 104 must further passinto the left atrium 18. As shown, the guide catheter 104 may reach theleft atrium 18 through a puncture in the intra-atrial septum 16.

In other implementations, such as for procedures associated with atricuspid valve, the guide catheter 104 may be passed through theinferior vena cava 12 into the right atrium 14, where it may then bepositioned and used to perform the procedure related to the tricuspidvalve. As described above, although many of the examples describedherein are directed to the mitral valve, one or more embodiments may beutilized in other cardiac procedures, including those involving thetricuspid valve.

Although FIG. 2 and many of the other examples described hereinillustrate a transfemoral approach for accessing a targeted cardiacvalve, it will be understood that the embodiments described herein mayalso be utilized where alternative approaches are used. For example,embodiments described herein may be utilized in a transjugular approach,transapical approach, or other suitable approach. For repair proceduresrelated to the mitral valve or tricuspid valve, delivery of theinterventional device 106 is preferably carried out from an atrialaspect (i.e., with the distal end of the guide catheter 104 positionedwithin the atrium superior to the targeted valve). The illustratedembodiments are shown from such an atrial aspect. However, it will beunderstood that the interventional device embodiments described hereinmay also be delivered from a ventricular aspect.

In some embodiments, a guidewire 107 is utilized in conjunction with theguide catheter 104. For example, the guidewire 107 (e.g., 0.014 in,0.018 in, 0.035 in) may be routed through the guide catheter 104 to thetargeted cardiac valve. Once the guidewire has been properly positioned,the guide catheter 104 may be removed. The guidewire 107 may then remainin position so that one or more interventional devices 106 can travelover the guidewire to the targeted cardiac valve (e.g., via a suitabledelivery catheter, sheath, and/or push rod).

Conventional Clip Deployment

FIGS. 3A and 3B schematically illustrate, in side view, deployment of aconventional tissue clip 114 at the mitral valve 20. The clip 114includes a pair of proximal arms 116 and an opposing pair of distal arms118, with each proximal arm 116 corresponds to an opposing distal arm118. The clip 114 configured so that an operator can controlarticulation of the arms to grasp leaflet tissue between the proximalarms 116 and distal arms 118, as shown. When the clip 114 is deployedand the leaflet tissue is grasped, the proximal arms 116 are positionedon the superior side of the valve leaflets (facing toward the leftatrium 18) and the distal arms 118 are positioned on the inferior sideof the valve leaflets (facing toward the left ventricle 22). Once theleaflet tissue has been sufficiently grasped, the clip 114 is moved to aclosed, lower profile configuration, and the actuator rod 120 isdetached and removed, as shown in FIG. 3B. The deployed and closedconfiguration is intended to affix the grasped leaflet tissue to promoteimproved leaflet coaptation and reduced regurgitation at the mitralvalve 20.

An example of a conventional tissue clip 114 is the MitraClip® deviceavailable from Abbott Vascular. A typical clip 114 has a closed cliplength of about 15 mm. The typical clip 114 has an open clip width ofabout 20 mm and a closed clip width of about 5 mm.

FIG. 4 illustrates the mitral valve 20 from a superior aspect. As shown,a set of conventional clips 114 have been deployed and implanted at themitral valve 20. In some circumstances, use of such conventional clips114 does not completely reduce regurgitation through the mitral valve20, and an amount of residual regurgitation remains. For example,residual regurgitation may occur at a gap 26 located between twoimplanted clips 114 and/or may occur at a gap 28 located between acommissure 24 and an implanted clip 114.

In some circumstances, it may not be clinically appropriate to deployanother such conventional clip 114 at a gap where residual regurgitationis occurring. For example, the targeted gap may be too small to fitanother clip 114. Further, even if the targeted gap is large enough tofit another clip 114 in a closed and deployed position (e.g., with aclosed clip width of about 5 mm), there may be insufficient space tosafely maneuver, articulate, and deploy the clip 114 at the targeted gapwithout entangling nearby tissues, damaging clip components, and/ordisplacing a previously placed clip. In other circumstances, use of anadditional clip 114 may be inappropriate because the clip 114 wouldgrasp too much of the relatively narrow gap and would risk causingstenosis of the valve. In such circumstances, the residualregurgitation, while not ideal, is often allowed to continue because itis preferable to risking valve stenosis.

Accordingly, there are many situations in which valve leakage exists butconventional repair devices and procedures are inappropriate. Thedevices, systems, and methods described below may be utilized in suchcircumstances to provide effective reduction of regurgitation. Althoughmany of the examples illustrated and described herein relate todeployment of an interventional device between two previously deployedtissue clips, it will be readily understood that the described featuresand components may be readily utilized in other applications whereleakage occlusion is intended. For example, one or more of theembodiments described below may be utilized to treat a paravalvularleakage (e.g., in a mitral valve, aortic valve, or other cardiac valve),other vascular leakages, or to treat leakage between an implanted deviceand a naturally occurring structure, such as between an implanted deviceand a valve commissure.

Embodiments described below may be deployed to effectively treat gaps ofabout 1 mm to about 10 mm, or about 2 mm to about 8 mm. Included in theforegoing ranges, gaps of about 5 mm or less (e.g., about 2 mm to 5 mm)may be effectively treated using one or more of the embodimentsdescribed below. Further, although the examples shown below illustratetreatment of a single gap, it will be understood that in at least someapplications, a plurality of gaps may be treated. For example, as shownby the dashed-line conventional clip 114 of FIG. 4, there may becircumstances where multiple treatable gaps exist, where one or more maybe located between two implanted clips and one or more may be locatedbetween an implanted clip and a valve commissure.

Tissue Tensioning Devices

FIGS. 5A through 5C illustrate deployment of an interventional deviceconfigured as a tissue tensioning device 200 configured to apply atensioning force along the line of coaptation of a targeted gap in acardiac valve. The views of FIGS. 5A through 5C show the mitral valve 20from the ventricular side. As shown in FIG. 5A, a gap 26 may existbetween two clips 114 previously deployed at the mitral valve 20. FIG.5B shows insertion of the tensioning device 200 within the targeted gap26. The illustrated tensioning device 200 includes a distal section 202,an intermediate section 206, and a proximal section 204. In theillustrated embodiment, the tensioning device 200 is formed as wirehaving free ends at the proximal section 204 which extend to formopposing members of the intermediate section 206 before meeting andclosing at the distal section 202.

The tensioning device 200 is configured so that at least theintermediate section 206 may be biased laterally outwardly. As shown inFIG. 5C, after positioning the tensioning device 200 within the gap 26,the intermediate section 206 is allowed to laterally expand along theline of coaptation. The laterally expanding structure of theintermediate section 206 abuts against the implanted clips 114 andforces them further away from one another to thereby assist in closingthe gap 26.

The tensioning device 200 is preferably formed with a width that isallows the device to fit within the targeted gap and provide thelaterally outward tensioning force. For example, the tensioning device200 may have a default, expanded width of about 1 to 3 mm greater thanthe targeted gap. In this manner, the tensioning device 200 can bepositioned within the gap in the laterally compressed state whichprovides the outward lateral tensioning force. The tensioning device 200is preferably sized for deployment at a gap of approximately 1 to 10 mm,or about 2 to 8 mm in width, including relatively small gaps of about 2to 5 mm in width. The length of the device may be up to about 9 mm, suchas about 5 to 9 mm.

The tensioning device 200 may be deployed, for example, by routing adelivery catheter carrying the tensioning device 200 through thetargeted gap 26 from the atrial side to the ventricular side, andunsheathing the tensioning device 200 to allow it to expand along theline of coaptation from the more compressed, smaller width profile shownin FIG. 5B to the expanded, larger width profile shown in FIG. 5C.

In the illustrated embodiment, the proximal section 204 of thetensioning device 200 includes free ends that extend or flare outwardlyto provide a greater overall width to the proximal section 204 relativeto the intermediate section 206. This feature may aid in preventing thetensioning device 200 from being forced distally through mitral valve 20and carried downstream into the ventricle. The illustrated embodiment isconfigured with a closed distal section 202 and an open proximal section204. The proximal section 204 may alternatively be closed in a mannersimilar to the distal section 202. In some embodiments, the proximalsection 204 is closed and the distal section 202 is open. In eachembodiment, however, it is preferred that at least the proximal section204 have a width greater than the intermediate section 206.

The illustrated tensioning device 200 is shown as a simple wirestructure. In other embodiments, the tensioning device may include aninterior wireframe assembly, elastomer film cover, and/or other interiorstructural elements. The tensioning device 200 may be formed from anysuitable biocompatible material, including biocompatible metals, alloys,polymers, and combinations thereof. In some embodiments, the tensioningdevice 200 is formed at least partially from a superelastic materialsuch as nitinol. The tensioning device 200 may also be formed from acobalt-chromium-nickel alloy (e.g., Elgiloy®), polypropylene, polyester,polylactide (e.g., PLLA or PLA), polyglycolide (PGA).

FIGS. 6A and 6B illustrate another embodiment of a tissue tensioningdevice 300 which may be delivered to a targeted gap to reduceregurgitation/leakage through the gap. FIG. 6A illustrates a perspectiveview of the tensioning device 300, and FIG. 6B illustrates thetensioning device 300 in a deployed position at the mitral valve 20. Thetensioning device 300 may be configured in some aspects (e.g.,materials, size) similar to tissue tensioning device 200 describedabove.

The illustrated tensioning device 300 includes a proximal section 304,an intermediate section 306, and a distal section 302. When deployed,the tensioning device 300 is positioned such that the distal section 302extends through the mitral valve 20 and into the ventricle, while theproximal section 304 remains on the atrial side of the mitral valve 20.The intermediate section 306 is positioned at the gap between theimplanted clips 114. In a manner similar to the tensioning device 200 ofFIGS. 5B and 5C, the intermediate section 306 of the tensioning device300 biases laterally outward along the line of coaptation and againstthe implanted clips 114 to assist in closing the gap between theimplanted clips 114.

The illustrated tensioning device 300 may be deployed at the mitralvalve 20 in a manner similar to the tensioning device 200 of FIGS. 5Band 5C. For example, the tensioning device 300 may be delivered to themitral valve 20 in a sheathed, low profile configuration. The distalsection 302 may be unsheathed first to open at the ventricular side ofthe targeted gap. Further unsheathing then exposes the intermediatesection 306 and proximal section 304.

In the illustrated embodiment, the distal section 302 and the proximalsection 304 are formed with deployed widths that are greater than thedeployed width of the intermediate section 306. This substantially flat“hourglass” shape can beneficially prevent the tensioning device 300from translating away from the valve 20 and embolizing downstream. Thetensioning device 300 may be formed as a braided or mesh wire structure.In some embodiments, the perimeter 308 of the device is formed as asolid wire to which the interior wire mesh attaches.

The tensioning device may be formed using any suitable biocompatiblematerial. The tensioning device 300 may also be formed from acobalt-chromium-nickel alloy (e.g., Elgiloy®), polypropylene, polyester,polylactide (e.g., PLLA or PLA), polyglycolide (PGA), for example. Insome embodiments, a nitinol wireframe structure is shape set in thedesired flat hourglass shape to form the tensioning device 300. Theinterior mesh may provide a textured surface which beneficiallyencourages tissue ingrowth. Alternatively, the interior mesh may beomitted.

Tissue Compression Devices

FIGS. 7A and 7B illustrate an embodiment of a tissue compression device400 which may be delivered to a targeted gap to reduceregurgitation/leakage through the gap. The tissue compression device 400is configured to compress captured tissue along a line orthogonal to theline of coaptation of the targeted cardiac valve tissue. The illustratedcompression device 400 includes a distal member 401 and a pair ofopposing arms 404 that extend proximally from the distal member 401. Thecompression device 400 is configured to grasp and hold leaflet tissuewithin an interior space between the opposing arms 404. The compressiondevice 400 may thereby aid in closing the gap and reducing regurgitationby compressing the grasped tissue. The illustrated compression device400 also includes frictional elements 412 for improving the engagementof the arms 404 with the leaflet tissue. The compression device 400 isconfigured to provide sufficient compression of grasped tissue for adesired period of time to enable tissue bridging/fusion without overlycompressing the tissue and causing necrosis or damage during delivery.

A delivery member 410 detachably couples to the distal member 401 at theattachment point 414. The compression device 400 may be deployed bypassing the delivery member 410 through the mitral valve 20 from theatrial side (the bottom side in FIGS. 7A and 7B) to the ventricular side(the upper side in FIGS. 7A and 7B). The delivery member 410 may then beretracted proximally to bring the interior side of the arms 404 intoengagement with the leaflet tissue on the ventricular side of the mitralvalve 20, as shown in FIG. 7A. The delivery member 410 is then detachedfrom the distal member 401 and removed, leaving the compression device400 in place on the ventricular side of the mitral valve 20 with theleaflet tissue affixed between the opposing arms 404 as shown in FIG.7B.

The illustrated compression device 400 is preferably formed from aflexible material capable of flexing sufficiently to allow the arms 404to position over and grasp the leaflets. The flexible compression device400 may therefore be deployed without requiring articulation of the arms404 or relatively complex operator control over arm position relative tothe valve 20. The illustrated compression device 400 is flexible suchthat when the arms 404 are moved apart and away from the defaultposition—such as when they are positioned over the leaflet tissue—thearms 404 will be biased back toward the default position, in a directionorthogonal to the line of coaptation, to provide a compressive forceupon the grasped leaflet tissue.

The compression device 400 may also be formed from acobalt-chromium-nickel alloy (e.g., Elgiloy®), polypropylene, polyester,polylactide (e.g., PLLA or PLA), polyglycolide (PGA). In someembodiments, the compression device 400 is formed from a bioabsorbablematerial. Such embodiments may provide for natural tissue bridging andfusion at the targeted gap. The compression device 400 is preferablysized for deployment at a gap of approximately 1 to 10 mm, or about 2 to8 mm in width. The compression device 400 may have a width of about 5 mmor less, such as about 2 to 5 mm. The length of the arms 404 may be upto about 9 mm, such as about 5 to 9 mm.

FIG. 8 illustrates alternative embodiments of tissue compression devices450 and 460. The compression devices 450 and 460 (as well as theadditional compression device embodiments described below) may beconfigured in some aspects (e.g., materials, size) similar tocompression device 400 described above. As shown by compression device450, the distal section 452 may be substantially rounded rather thanangular. As shown by compression device 460, the distal section 462 mayinclude a neck 466 configured to act as a flexible, living hinge fromwhich the extending arms 464 can flex. Both the compression device 450and the compression device 460 include arms 454 and 464 which flareoutwardly at their proximal ends. The flared construction may assist incapturing leaflet edges and bringing leaflets into the interior spacebetween the opposing arms as the device is retracted proximally over theleaflets.

FIGS. 9A and 9B illustrate use of the compression device 460 inconjunction with an atrial anchor 468. FIG. 9A is a view from theventricular side, while FIG. 9B is a cross-sectional side view. As shownin FIG. 9B, the atrial anchor 468 is attached to the compression device460 at attachment point 470. The compression device 460 may be deployedon the ventricular side of the valve 20 in the manner described abovewith respect to compression device 460. The atrial anchor 468 ispositioned on the atrial side, and is sized with a width that is greaterthan the width of the compression device 460 and preferably also exceedsthe width of the gap so as to prevent movement of the atrial anchor 468and attached compression device 460 downstream from the valve 20. Theatrial anchor 468 may be formed from a mesh, latticed, or otherwisetextured material that encourages ingrowth of the compressed leaflettissue affixed against the atrial anchor 468.

The compression device 460 and the atrial anchor 468 may be delivered inone piece as an integral device. Alternatively, the compression device460 and atrial anchor 468 may be delivered sequentially and then lockedtogether at the attachment point 470. For example, the atrial anchor 468may be unsheathed or otherwise delivered to the atrial side of thetargeted gap. The compression device 460 may then be routed through thetargeted gap to the ventricular side, then retracted back untilmechanically engaged with the atrial anchor 468. In alternativeembodiments, a suture or other suitable connection member may be used toconnect the compression device 460 and atrial anchor 468. Although theparticular compression device 460 is illustrated here, it will beunderstood that other compression device embodiments described hereinmay also be utilized with an atrial anchor in a similar manner.

FIGS. 10A and 10B illustrate another embodiment of a tissue compressiondevice 500 which may be delivered to a targeted gap to reduceregurgitation/leakage through the gap. FIG. 10A is a view of the mitralvalve 20 from the ventricular side and FIG. 10B is a cross-sectionalview taken along the line of coaptation. The compression device 500includes a distal member 501 and two arms which extend proximally fromthe distal member 501. A first arm loops back distally to form twoextended outer members 502 and 504. The second arm extends proximally toform an inner member 506. The inner member 506 extends between the outermembers 502 and 504. The outer members 502 and 504 and the inner member506 are connected in a clip configuration such that when deployed at thetargeted gap, the outer members 502 and 504 may be positioned on oneside of the captured leaflets while the inner member 506 is positionedon the opposite side of the captured leaflets.

As shown in FIG. 10B, the inner member 506 is laterally offset to extendbetween the outer members 502 and 504. With this configuration, when thecompression device 500 is deployed, the captured leaflet tissue is notcompressed directly between any two hard structures. The offset lines ofcompression may prevent over-compression of tissue to avoid injury andnecrosis. Some embodiments may include barbs or other frictionalelements (not shown) to promote engagement with captured tissue.

The compression device 500 may be delivered in a manner similar to thecompression device 400 as described in relation to FIGS. 7A and 7B. Forexample, a delivery member may attach to the distal member 501. Thecompression device 500 may be delivered to the ventricular side of thevalve 20, and then retracted proximally to bring the outer members 502and 504 and inner member 506 into position on opposite sides of thegrasped leaflets.

FIGS. 11A through 11C illustrate in cross-sectional side view anembodiment of a tissue compression device 600 having self-closingfeatures. A delivery catheter 610 is shown with a distal end deliveredthrough the mitral valve 20 to the ventricular side (the upper side inthe Figures). The compression device 600 is unsheathed and deployed fromthe delivery catheter 610 with the proximal free ends 604 extendingfirst out of the delivery catheter. An inner push rod (not shown), forexample, may extend within the delivery catheter 610 to enable pushingof the compression device 600 distally out of the delivery catheter 610.As shown in FIG. 11B, further deployment of the compression device 600out of the delivery catheter 610 allows the proximal free ends 604 tosweep laterally outwardly and rotate back toward the axis of thedelivery catheter 610. As shown in FIG. 11C, further deployment allowsthe proximal free ends 604 to wrap around proximally on opposite sidesof the leaflets of the mitral valve 20 and to engage with the outersurfaces of the leaflets. The compression device 600 may then bedetached from the delivery catheter 610 and the delivery catheter 610removed.

The compression device 600 is formed from a suitable shape memorymaterial (e.g., nitinol) processed at a transition temperature to setthe desired final deployed shape. The compression device 600 ispreferably processed at a suitably low temperature to allowstraightening and installation into the lower profile shape within thedelivery catheter 610 without exceeding the strain properties andcausing plastic deformation. Once exposed to the relatively elevatedtemperature within the body, the unsheathed or extruded device willprogressively transition in shape to the final position capable ofgrasping leaflet tissue.

Combination Compression/Tensioning Devices

FIGS. 12A through 12D illustrate an exemplary embodiment of a device 700configured to both tension and compress tissue at a targeted gap. Asdescribed below, the device 700, when deployed at a targeted gap of acardiac valve, provides tension along the line of coaptation of the gapwhile simultaneously providing compression of grasped tissue along aline orthogonal to the line of coaptation.

As shown in FIG. 12A, the combination device 700 includes a pair of freeends 704 which each angle at bend 706 and then extend as a lateralmember 712. Each lateral member 712 then loops at bend 708 and extendsas a longitudinal member 710. The opposing longitudinal members 710 meetand close at a proximal end 702. Although not shown, the combinationdevice 700 may optionally include a mesh or webbing to encourage tissueingrowth.

As shown in FIG. 12B, the combination device 700 may be flexed so thatthe longitudinal members 710 move inwardly and the overall width of thedevice 700 is reduced. From such a constrained position, the device willprovide an outward lateral force toward the default, wider positionshown in FIG. 12A.

FIGS. 12C and 12D illustrate the combination device 700 in a deployedposition at a targeted gap between two conventional clips 114. FIG. 12Cis a side view showing the ventricular side of the valve 20 and FIG. 12Dis a view from a position inferior to the valve 20. When positionedwithin the gap, the lateral outward tensioning force 730 provided by theopposing longitudinal members 710 can cause the device 700 to abutagainst and force the clips 114 apart from one another. This will bringleaflets of the gap into contact with one another to assist in closingthe gap. In addition to the tensioning force 730, the combination deviceprovides a compressive force 720 against the grasped leaflet tissue. Thelateral members 712 are positioned on opposite sides of the graspedleaflets and are biased toward one another to compress the tissue heldbetween.

The combination device 700 may be deployed in a manner similar to thedeployment of compression device 600 shown and described in relation toFIGS. 11A through 11C. For example, the combination device 700 may beformed from a suitable shape memory material (e.g., nitinol) anddeployed by unsheathing the device 700 at the targeted gap. The freeends 704 may be unsheathed first and allowed to sweep around on oppositesides of the leaflets to form the lateral members 712. The remainder ofthe device 700, including the longitudinal members 710 and proximal end702, may then be unsheathed at the desired position within the targetedgap.

Force-Distributing Features

FIGS. 13A through 13D illustrate embodiments of tissue compressiondevices having force-distributing features. FIGS. 13A through 13C showvarious exemplary wire patterns which may be utilized at one or moresections of a compression device to provide greater effective surfacearea. The relatively high effective surface area better distributescompressive forces upon the grasped tissue while also providingeffective contact and tissue engagement. FIG. 13A illustrates a portionof a compression device 800 having a looping or spiraling pattern. FIG.13B illustrates a portion of a compression device 802 having aserpentine or winding pattern of extensions 808. FIG. 13C illustrates aportion of a compression device 804 having a forked pattern with aplurality of extensions 812 radiating from a common point 810.

Force-distributing features such as those illustrated may be includedwith any of the compression or combination compression/tensioningdevices described above. For example, any of the illustrated forcedistributing patterns, or combinations thereof, may be used at the freeends of the embodiments shown in FIGS. 10A through 12D.

FIG. 13D illustrates the compression device 800 as deployed at atargeted gap of the mitral valve 20. As shown, the force-distributingspiral pattern is employed on one side of the grasped tissue and aninner member 806 is disposed on the opposite side of the grasped tissue.The spiral pattern functions to distribute applied forces and preventoverly compressing tissue grasped between the spiral pattern and theinner member 806. Alternative embodiments may include one or moreforce-distributing features on both sides.

Self-Centering Delivery Catheter and Sizer

FIGS. 14 through 15B illustrate exemplary embodiments of deliverycatheters having a self-centering feature that provides desiredalignment to the cardiac valve anatomy. As shown in FIG. 14, a deliverycatheter 900 includes a pair of fins 906 extending laterally from thelongitudinal axis of the delivery catheter 900 (the leaflets of themitral valve 20 are shown here as transparent to better illustrate thedelivery catheter 900). The fins 906 are positioned near the distal endof the delivery catheter 900 so that when the distal end of the deliverycatheter 900 is positioned at the targeted gap, the fins 906 will causethe delivery catheter 900 to rotate as needed to align with the line ofcoaptation of the mitral valve 20.

For example, if the projected fins 906 are not aligned to the line ofcoaptation during the approach to the mitral valve 20, the fins 906 willabut against the atrial facing surfaces of the leaflets. Because theleaflets slope closer to each other in the ventricular direction towardthe leaflet edges, further movement of the delivery catheter 900 in theventricular direction will cause the delivery catheter 900 to rotate sothat the fins 906 will better fit within the wedge shape of theleaflets. The delivery catheter 900 may travel over a previouslypositioned guidewire 901, as shown.

The self-centering feature can beneficially ensure that aninterventional device passed through the delivery catheter 900 isproperly aligned to the line of coaptation of the valve 20. For example,the interventional device carried within the delivery catheter 900 maybe rotationally keyed to the delivery catheter such that by ensuringalignment of the delivery catheter 900 also ensures alignment of theinterventional device.

The fins 906 are shown here in a symmetric arrangement with eachopposing fin having a substantially equal width. When used, such anembodiment will operate to position the distal end of the deliverycatheter 900 at the center of the targeted gap (e.g., between the twoimplanted clips 114). Alternative embodiments may have fins with anon-symmetric arrangement to offset from the center of the gap theposition the distal end of the catheter. Such an offset, non-symmetricembodiment may be used where particular patient anatomy and/orprocedural requirements require deployment of an interventional deviceoff from the center of a targeted gap.

FIGS. 15A and 15B illustrate an embodiment of a delivery catheter 1000having adjustable-width fins. FIG. 15A shows a distal end 1002 of thedelivery catheter 1000 with the fins 1004 in a retracted position. Wires1004 (or strips, ribbons, or other suitable structures) pass through theinterior of the delivery catheter 1000 and are attached near the distalend 1002. A pair of skives 1006 are also included near the distal end1002. As shown in FIG. 15B, the wires 1004 may be translated distallysuch that portions extend laterally out of skives 1006. The laterallyextended wires 1004 may then function as the self-centering fins whichalign the delivery catheter 1000 to the line of coaptation whendelivered to the cardiac valve. In some embodiments, the distal portionof the delivery catheter 1000 includes a coating of an elastomermaterial or other suitable material covering at least the skives 1006.In this configuration, the extending wires 1004 which form the fins arecovered and there is no gap between the extended wires 1004 and theskives 1006.

The width of the fins is controllable by translating the wires 1004relative to the body of the delivery catheter 1000. For example, movingthe wires 1004 distally will force greater lengths out of the skives1006 to increase the effective width of the fins. Likewise, retractingthe wires 1004 proximally will pull more wire length in through theskives 1006 to shorten the width of the fins. The wires 1004 may extendproximally to a handle and may be operatively coupled to one or morecontrols so that an operator can control fin adjustment throughmanipulation at the handle (see, e.g., FIG. 1). In some embodiments, thewires 1004 are independently controllable, and the widths of eachopposing fin may be adjusted to a symmetric or non-symmetricconfiguration.

Although embodiments of FIGS. 14 through 15B are described above in thecontext of their use as delivery catheters, it will be understood thatthey may also be utilized as sizers for informing an operator as to thesize of the targeted gap. Determining the size of a targeted gap maytherefore inform the selection and/or sizing of the interventionaldevice to deploy at the gap. An operator may pass the fins into thetargeted gap and use the width of the fins to determine the size of thegap. For example, if real-time monitoring (e.g., via echo/Doppler)confirms that regurgitation is sufficiently reduced while the fins arepositioned within the gap, the properly coapted gap will be determinedto be about the same width as the fins. When configured as sizers, thesizers need not necessarily also be capable of delivering aninterventional device to the targeted gap. In some implementations, aseparate sizer or set of sizers may be utilized to determine gap size,and a separate delivery catheter may then be used to delivery aninterventional device.

Attachment/Detachment Mechanisms

FIGS. 16A through 16C illustrate various exemplary mechanisms forattaching and detaching at least some of the interventional devicesdescribed herein. For example, the illustrated interventional device1100 may generically represent any of the tensioning devices and/orcompression devices illustrated in FIGS. 5A through 13D. In FIG. 16A, aninterventional device 1100 is shown sheathed within a delivery catheter1110. An inner member 1128 (formed as a push rod or other suitablestructure) couples to the interventional device 1100 at attachment point1102.

FIG. 16B illustrates various attachment/detachment mechanisms that maybe utilized, including a hook member 1120, a fitting member 1122, athreaded member 1124, or a clamp member 1126. The interventional device1100 is configured so that the attachment point 1102 matches theparticular construction of the of the attachment/detachment mechanism ofthe inner member 1128. Other embodiments may include one or morealternative locking mechanisms suitable for detachably coupling theinterventional device 1100 to the inner member 1128. For example, anirreversible shearing feature may be designed to fail at a given stressto detach the inner member 1128 from the interventional device 1100.

FIG. 16C shows retraction of the delivery catheter 1110 relative to theinner member 1128 and resulting unsheathing of the interventional device1100. Following unsheathing and deployment, the inner member 1128 may bedetached from the interventional device 1100 and removed. In preferredembodiments, the delivery catheter 1110 functions as a single outersheath, however additional (e.g., telescoping) sheaths may be utilizedif staged deployment is desired.

The terms “approximately,” “about,” and “substantially” as used hereinrepresent an amount or condition close to the stated amount or conditionthat still performs a desired function or achieves a desired result. Forexample, the terms “approximately,” “about,” and “substantially” mayrefer to an amount or condition that deviates by less than 10%, or byless than 5%, or by less than 1%, or by less than 0.1%, or by less than0.01% from a stated amount or condition.

Elements described in relation to any embodiment depicted and/ordescribed herein may be substituted for or combined with elementsdescribed in relation to any other embodiment depicted and/or describedherein. For example, any of the interventional device embodimentsillustrated in FIGS. 5A to 13D may be utilized with any of the deliverycatheter or attachment/detachment mechanism embodiments illustrated inFIGS. 14 through 16C.

1. An interventional device for compressing cardiac valve tissue at atargeted gap, the device comprising: a distal member; and a pair ofopposing arms flexibly joined to the distal member, each arm extendingproximally from the distal member to a free end, the pair of opposingarms defining an interior space between the arms for holding cardiacvalve tissue, wherein the arms have a default position, the arms beingflexibly moveable apart from one another away from the default positionto increase the interior space and to enable receiving cardiac valvetissue within the interior space, and wherein the arms are configured tobe biased toward the default position when moved apart from one another,the arms thereby providing a compressive force upon cardiac valve tissueheld within the interior space.
 2. The interventional device of claim 1,wherein the device is configured in size and shape for deployment at atargeted gap measuring about 2 to 8 mm.
 3. The interventional device ofclaim 1, further comprising a plurality of frictional elementsconfigured to engage with the cardiac valve tissue held within theinterior space, the frictional elements being disposed on an interiorside of one or both of the arms.
 4. The interventional device of claim1, wherein one or both of the free ends flare outwardly.
 5. Theinterventional device of claim 1, further comprising a neck sectionjoining the distal member to the arms, the neck section being configuredas a flexible living hinge from which the arms can flex.
 6. Theinterventional device of claim 1, further comprising an attachment pointat the distal member for attaching to a delivery device.
 7. Theinterventional device of claim 1, further comprising an anchorconfigured to couple to the distal member, the anchor extending throughthe interior space, and the anchor having a width greater than a widthof the distal member or the arms.
 8. The interventional device of claim7, wherein the anchor includes a textured surface configured toencourage tissue ingrowth.
 9. The interventional device of claim 7,wherein the anchor has a width of about 5 to 8 mm.
 10. Theinterventional device of claim 1, wherein a first arm extends proximallyfrom the distal member to form an inner member, and wherein a second armextends proximally from the distal member and loops back distally toform a pair of outer members, the inner member being laterally offsetfrom each of the outer members.
 11. The interventional device of claim1, wherein the device is formed from a shape-memory material such thatthe free ends, when deployed distally, sweep around proximally to grasptargeted cardiac valve tissue.
 12. The interventional device of claim 1,wherein one or both of the arms include a force-distributing wirepattern.
 13. An interventional system for compressing cardiac valveleaflet tissue at a targeted gap of a cardiac valve, the systemcomprising: an interventional tissue compression device, the compressiondevice comprising: a distal member; and a pair of opposing arms flexiblyjoined to the distal member, each arm extending proximally from thedistal member to a free end, the pair of opposing arms defining aninterior space between the arms for holding leaflet tissue, wherein thearms have a default position, the arms being flexibly moveable apartfrom one another away from the default position to increase the interiorspace and to enable receiving leaflet tissue within the interior space,and wherein the arms are configured to be biased toward the defaultposition when moved apart from one another, the arms thereby providing acompressive force upon leaflet tissue held within the interior space;and a self-centering delivery catheter, the delivery catheter includinga pair of laterally extending fins extending from a distal section ofthe delivery catheter, the fins enabling alignment of the deliverycatheter with a line of coaptation at the targeted gap.
 14. The systemof claim 13, wherein the fins are configured to be intra-procedurallyadjustable in width.
 15. The system of claim 14, wherein the distalsection of the delivery catheter includes a pair of skives and acorresponding pair of wires laterally extendable through the skives toform the fins.
 16. The system of claim 15, wherein the wires extendthrough a lumen of the delivery catheter such that width of the fins iscontrollable via translation of the wires.
 17. A method of reducingregurgitation through a cardiac valve by compressing leaflet tissue at atargeted gap of the cardiac valve, the method comprising: delivering aninterventional tissue compression device to the targeted gap, thecompression device comprising: a distal member; and a pair of opposingarms flexibly joined to the distal member, each arm extending proximallyfrom the distal member to a free end, the pair of opposing arms definingan interior space between the arms for holding leaflet tissue, whereinthe arms have a default position, the arms being flexibly moveable apartfrom one another away from the default position to increase the interiorspace and to enable receiving leaflet tissue within the interior space,and wherein the arms are configured to be biased toward the defaultposition when moved apart from one another, the arms thereby providing acompressive force upon leaflet tissue held within the interior space;and deploying the compression device at the targeted gap to compress theleaflet tissue and reduce regurgitant flow through the targeted gap. 18.The method of claim 17, wherein the targeted gap is at a mitral valve.19. The method of claim 18, wherein the targeted gap is disposed betweentwo previously deployed implants or between a previously deployedimplant and a valve commissure.
 20. The method of claim 18, wherein thecompression device is delivered to the ventricular side of the mitralvalve, and then is retracted proximally to enable the arms to grasp theleaflet tissue at the ventricular side of the mitral valve.